Making molds

[Mystic32cat]

 I am making a set of custom headers and I would like to build a mold so I could use it on other models. How do I make a mold with stuff you would have at home?(like silicone, hot glue etc..)

[aurfalien]

Well, when I cast, I use a silicon RTV for the mold itself.  Its not home grade fromage but rather specific to mold making.

You'd use your hot glue gun/silicone to make the box that contains the mold.

Here's a cool video;

This guy uses standard grade stuff like what you wish to do, I've never used it but intrigueing indeed.  He doesn't demonstrate, simply talks through but still cool;

[Longbox55]

I'm going to perfectly honest, as I have made molds both with household materials and mold making specific materials, you'll be well ahead by going with the materials that are for making molds. While you can make relatively simple molds using household or automotive RTV, it's a tricky process that takes time and patience. The mold failure rate is also very high, as those types of RTV tend to either stick to the part being molded, r do not properly cure due to the thickness required to make a good mold. That said, I would really only suggest using that type RTV for very small molds, such as scripts or lenses that do not require much thickness. You also do have to have a good mold release to prevent it from sticking, but also that will allow you to apply the RTV without it sliding off. It can be tricky to do.

For what you're wanting to do, however, I would suggest getting a small mold making kit. Hobby Lobby has them, and with the coupon, they're not to pricey. Using the kit, you'll be able to do a 2 part mold, and get all of the details and complex shapes without too much trouble.

I would also suggest that you check out the assorted videos on YouTube. The company that made the top one Brian posted, Brick In The Yard, as several good videos for resin casting and mold making, though much of what they have is geared more towards effects makeup and props than model building. Alumalite and Smooth On both have good videos as well.

[aurfalien]

+1 Longbox55!

I've used both PinkySil and Allumilte RTV fromage.

My views;

The Alumilte stuff is a harder mold taking 12-24 hours for proper cure.  I feel its well suited for small detail like duping cards etc...

PinkySil is a much softer mold taking 30 minutes to cure.  Its well suited for stuff like hoods, doors etc...

There are other RTV based brands which are reviewed here so check around.  I'd suggest buying the Alumilte kit to start with, it has;

RTV silicone

Blue Clay (which I hate as it stains my hands).

2 part resin

Mold release agent

Measuring cups and wodden stirs.

Hobby Lobby with a 40% coupon would cost ~$40.

 

[Len Woodruff]

Interesting. I have done bodies using the standard OOMO 30 from SmoothOn. 

[Longbox55]

I'll agree with you on the Alumilite silicone that comes in the kits. I rarely use it myself. I primarily use their High Strength 3 silicone, which is a soft pink rubber. Much easier to work with.

[aurfalien]

I'll agree with you on the Alumilite silicone that comes in the kits. I rarely use it myself. I primarily use their High Strength 3 silicone, which is a soft pink rubber. Much easier to work with.

Cool, that will be my next purchase.  Although I undrstand that the SmoothOn stuff as Len mentioned is very good.

Edited December 16, 2015 by aurfalien

[louie]

I just wanted to say thank you for posting the video links. Some really great stuff on there. This is a Great Thread, and I do appreciate it. Always wanted to give resin casting a try but had absolutely no idea how to start. Thanks for sharing this one.      Jeff 

[aurfalien]

I just wanted to say thank you for posting the video links. Some really great stuff on there. This is a Great Thread, and I do appreciate it. Always wanted to give resin casting a try but had absolutely no idea how to start. Thanks for sharing this one.      Jeff 

Cool deal.

Check the Alumilte site, I started there when doing my first castings.

They have 2 types of products, the traditioanl stuff thats covered in this thread and this newer instant thing.  Its were you shape a mold quickly as it dries fast and poor your resin into it.  Pretty cool stuff;

https://www.youtube.com/watch?v=CfK0D9D-X48

Edited December 17, 2015 by aurfalien

[louie]

Cool deal.

Check the Alumilte site, I started there when doing my first castings.

They have 2 types of products, the traditioanl stuff thats covered in this thread and this newer instant thing.  Its were you shape a mold quickly as it dries fast and poor your resin into it.  Pretty cool stuff;

https://www.youtube.com/watch?v=CfK0D9D-X48

I never knew those videos existed. Awesome, thanks for posting the link. That's why I love it here, great people helping out other people like me to learn more about this great hobby of ours. Again thank you.    Jeff